First,the most material to scan is in a good quality.
I'm using an older Canon CanoScan 8400F and this only in 400dpi modus.
After scanning, all images are imported to Corel Photophaint X4.
In Corel, I'm processing each image separately, like denoising, remove moire or scratches, adjust contrast/colour etc.
All images are saved to TIF oder TGA,after resizing to 2k horizontal resolution, this is enough for the source material.
For the forum to post, I'm export the images to JPG with 4:4:4 (its a important point for jpeg) in a fair quality.